DRY Slides with ---
Never repeat yourself, let Quarto do it
Quarto Extension
The Problem
Too much content, not enough slides
When a topic spans multiple slides, you end up writing the same heading over and over:
This violates the DRY principle and makes refactoring painful.
The Solution
The cascade extension
A filter that repeats the heading chain automatically when you use --- to create a new slide.
- Works only for
revealjsoutput. - Repeats the full heading hierarchy, not just the immediate title.
The cascade extension
This very slide was created with ---.
No heading was written in the source; it was repeated from the previous slide.
Nested headings work too
Deep dive
Content under a nested heading structure.
Nested headings work too
Still diving
Both ## Nested headings work too and ### Still diving on the slide. Only parent headings above this ### level are repeated from the previous slide.
Fine Tuning
Opting out with {.no-cascade}
A pinned subheading
A heading marked {.no-cascade} stays here but is never repeated.
Opting out with {.no-cascade}
Only ## Opting out with {.no-cascade} is repeated. The ### A pinned subheading is not, because of the {.no-cascade} class.
Limiting the depth
Level three heading
This presentation sets depth: 2, so only the top two heading levels cascade.
Level four heading
This level-four heading is below the depth limit.
Limiting the depth
Level three heading
Both ## Limiting the depth and ### Level three heading are repeated. The #### Level four heading is dropped because it sits beyond depth: 2.
Per-heading depth override
Sub-heading kept off the chain
The heading attribute cascade-depth="1" overrides the document-level depth: 2 here.
Per-heading depth override
Only ## Per-heading depth override is repeated; the ### Sub-heading kept off the chain is dropped because of the per-heading override.
Inside Blocks
Callouts split too
Callouts split too
A multi-part tip
First half of the tip.
Callouts split too
A multi-part tip
Second half: the heading and the callout were repeated automatically.
Regular divs split too
Regular divs split too
A side note, first part.
Regular divs split too
Second part, still in the margin, on a new slide.
Cross-reference does not break
(i.e., ^%a+%- ID)
Tip 1: A multi-part tip
First half of the tip.
Second half: the heading and the callout were repeated automatically.
Before and After
Before: repetitive markdown
After: DRY markdown
Fewer lines, single source of truth for headings, and zero risk of typos.